Method and Plant for the Treatment of Fibrous Material Susceptible to Degradation by Biological Activity

Abstract

Material susceptible to degradation by biological activity, before all by microorganisms like bacteria and fungi, is treated with ozone. The ozone penetrates the material and not only deactivate the active organisms themselves, but also spores of bacteria and fungi. The ozonization is performed in at least one cycle consisting of subjecting the material to underpressure, e.g. of 500 mBar, in a vessel, then filling the vessel with ozone containing gas. In a preferred embodiment, the ozonization may be preceded by at least one steaming cycle, consisting essentially of applying vacuum, then filling the vessel with steam, notably with steam of about 80° C.

1 . Method for treating fibrous material prone to degradation by biological activity, wherein the material is subjected at least once to an ozonization cycle comprising the steps of 
 subjecting the material to underpressure in a closed vessel, and subsequently    applying an ozonization step to the material, the ozonization step comprising filling the vessel with a gas having an effective ozone concentration, optionally followed by leaving the material in the ozone containing atmosphere, so that the material is effectively penetrated by the gas in order to destroy microorganisms in the material by the ozone.    
   
   
       2 . Method according to  claim 1 , wherein the underpressure is a pressure of at most about 500 mBar (50 kPa).  
   
   
       3 . Method according to  claim 1 , wherein the underpressure is a pressure of about 100 mBar (10 kPa) to about 500 mBar (50 kPa).  
   
   
       4 . Method according to  claim 1 , wherein the ozonisation step has a duration of from 3 minutes to 20 minutes.  
   
   
       5 . Method according to  claim 1 , wherein at least the final ozonization step has a duration of about 5 minutes.  
   
   
       6 . Method according to  claim 1 , wherein the ozone content of the ozone containing gas is at least 4 wt.-%.  
   
   
       7 . Method according to  claim 1 , wherein the ozone containing gas is produced by passing a gas consisting of air up to pure oxygen through an ozone generator converting oxygen into ozone.  
   
   
       8 . Method according to  claim 7 , wherein the ozone containing gas is stocked in an ozone reservoir and the vessel is filled substantially by emptying the ozone reservoir into the vessel.  
   
   
       9 . Method according to  claim 1 , wherein the material comprises compacted or uncompacted raw cotton bales.  
   
   
       10 . Method according to  claim 1 , wherein the material is bales, bobbins and/or pieces of textile webs, fabrics, threads, felts, fleeces and/or yarns consisting at least partially of cotton and/or other fibrous materials susceptible to degradation by biological activity.  
   
   
       11 . Method according to  claim 1 , wherein after completion of the ozonization, the material is wrapped in an essentially microorganism-tight packaging in order to keep the ozone within the material.  
   
   
       12 . Method according to  claim 1 , wherein preceding or interspersed with the ozonization, the material is subjected to a steaming treatment comprising at least one cycle with the steps of 
 subjecting the material to underpressure in a closed vessel    filling the vessel with steam in order to heat the material thoroughly to a temperature where biological organisms are destroyed or inactivated.    
   
   
       13 . Method according to  claim 12 , wherein the last steaming cycle is followed by at least one final ozonization cycle, the creation of underpressure of the first of the final ozonisation steps being optionally constituted partially or totally by the underpressure prevailing at the end of the preceding steaming cycle.  
   
   
       14 . Plant for performing the method according to  claim 1 , comprising a vessel capable to be essentially gas-tight closed, the vessel being connected to at least an ozone source and a vacuum pump.  
   
   
       15 . Plant according to  claim 14 , comprising additionally a steam source, so that the vessel can be filled with steam.  
   
   
       16 . A fibrous material prone to degradation by biological activity, wherein the material is wrapped in essentially microorganism-tight packaging and the free space within the material is filled with a gas containing ozone in order to suppress the biological activity.  
   
   
       17 . The fibrous material according to  claim 16 , wherein the material is a wrapped cotton bale, bobbins and/or pieces of textile webs, fabrics, threads, felts, fleeces and/or yarns consisting at least partially of cotton and/or other fibrous materials susceptible to degradation by biological activity.